LSJ
α, ον (formed like εἰκοσταῖος, etc.), for many days past, Eub. 133 cod. ; — written πολλασταῖος, PSI 5.528.12 (iii BC).
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
wird aus Eubul. angeführt, Cram. Anecd. 1.369.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)